Modern firearms generally use cartridges consisting of a metal case containing smokeless powder and holding the projectile. A primer held in the metal case ignites the contained propellant, when struck, to discharge the projectile. Shot-gun shells, use a brass base and a cardboard or plastic tube to hold powder, wads and shot. Neither the cartridges nor the tubes are not consumable and must be ejected after each discharge. Most of these may be used for reloading.
The concept of ammunition which has a consumable casing has had the attention of numerous people including inventors, due to the benefits of lightness, no brass recovery, etc. For example, U.S. Pat. No. 3,513,776 to Driscoll on May 25, 1970, describes a consumable cartridge case formed of carbon filaments embedded in matrix of solid propellant. Kravle in U.S. Pat. No. 3,398,684 of Aug. 27, 1968 described a projectile having its breech end formed with a charge-containing cavity having the walls and bottom lined with nitrocellulose fibers which have a density less than nitrocellulose per se. Johnson in U.S. Pat. No. 3,008,258 of Nov. 14, 1961 teaches a solid propellant formed into a cartridge shape with a primer in the rear end, similar to a brass cartridge. A firearm for such cartridges must specially be made to accommodate the cartridge. Kintzinger in U.S. Pat. No. 2,632,391 of Mar. 24, 1953 suggests a cartridge case made of plastic explosive nitrocellulose. The primer is located adjacent the projectile and exists with the projectile.
Larson, U.S. Pat. No. 3,558,008 provided a consumable case which was threaded on to an adapter and the projectile was threaded onto the adapter. This used a low-nitrogen nitro-cellulose binder for the molded propellant.
In U.S. Pat. No. 3,670,649 Hartlein et al produced a nonmetallic cartridge of fiber-reinforced nitrocellulose having from 0.1 to 3 percent of an organosilicone compound incorporated therein to render the casing impermeable to liquid water. The organosilicone resin is applied by spraying, dipping or brushing to provide a thin coating on the casing.